This application relates generally to gas turbine engines and, more particularly, to a method and apparatus for monitoring gas turbine engine Life Limited Parts (LLP).
At least some known gas turbine engines include a fan, a compressor, a combustor, a high pressure turbine, a low pressure turbine, and at least one shaft, wherein at least one of the fan, the compressor, and the high and low pressure turbines typically include a plurality of disks, spools, that are included in the list of LLP for the gas turbine engine.
Moreover, at least some known gas turbine engines are installed in an aircraft to provide the propulsion force necessary to operate the aircraft during all flight conditions. To facilitate reducing the probability that a gas turbine engine life limited part will fail during flight conditions, guidelines have been promulgated that instruct the maintenance personnel to condition, inspect and/or replace the engine life limited part after the engine life limited part has been operated for a predetermined quantity of cycles or hours.
More specifically, life tracking of turbofan engine life limited parts such as, a high pressure turbine rotor, is performed using a plurality of engine parameters such as, measured temperatures, pressures, speeds and/or various other engine parameters, that are recorded at specific engine operating conditions. This engine data is typically gathered on a fleetwide basis, and processed to define average flight conditions, and to calculate life limited part stress levels, temperatures and lives for each engine life limited part.
For example, at least one known aircraft utilizes a data recorder to facilitate collecting and recording a selected portion of the engine data. Moreover, on at least one known commercial aircraft, engine data is collected using a data recorder commonly referred to as a Quick Access Recorder (QAR).
However, recording a portion of the engine data utilizing either the data recorder or the quick access recorder can be problematic. For example, known aircraft do not include a system that is configured to automatically download the engine data from the aircraft to a ground facility. Therefore, the engine data is manually retrieved from either the aircraft data recorder or the quick access recorder. Moreover, known aircraft data recording devices have a limited capacity such that only a portion of the engine data, collected during a limited quantity of flights, can be recorded at a given time. Therefore, known data recorders are configured to sample only a portion of the engine data that is available on a limited quantity of flights. Accordingly, only a limited quantity of the data available from the gas turbine engine, is utilized to calculate stresses and lives of the individual gas turbine life limited parts.